OK, so first of all, I know this has been beat to death, but do you honestly think it would be stupid for Rockstar to create a GTA game for Wii? Are you seriously trying to tell me that you wouldn't buy a Wii version of GTA, even if you already had GTA IV on PS3 or 360? If you say wouldn't buy it, then you're lying.
The fact is, that the entire control scheme would make people curious, and they would probably buy it just to have it. After all, as of 12/31/07, Nintendo has shipped over 20 million units worldwide, and has sold more units than PS3 and 360 combined in the US.
Honestly, I think it would be an idiotic financial decision for Rockstar NOT to create a GTA build for the Wii. I know I would buy it, and yes, you probably would too...even if just out of curiosity.